This application is based on and claims priority to Japanese Patent Application No. 2001-054800, filed Feb. 28, 2001, the entire contents of which are hereby expressly incorporated by reference.
1. Field of the Invention
The present invention relates to cooling systems for marine engines. More specifically, the present invention relates to an improved cooling water jacket arrangement within a lubrication oil reservoir.
2. Description of Related Art
Personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. A relatively small hull of the personal watercraft defines a rider""s area above an engine compartment. An internal combustion engine powers a jet propulsion unit which propels the watercraft. The engine lies within the engine compartment in front of a tunnel formed on an underside of the hull. The jet propulsion unit, which includes an impeller, is placed within the tunnel. The impeller has an impeller shaft driven by the engine. The impeller shaft usually extends between the engine and the jet propulsion device through a bulkhead of the hull tunnel.
Four-stroke engines include lubrication systems arranged to supply lubrication oil to various portions of their engines, such as the crankshaft chamber and camshaft chamber. Desirably, a volume of lubrication oil is provided within a reservoir to be available for supply to the engine. The lubrication oil is permitted to cool upon being returned to the reservoir before again being supplied to the engine. As the oil pools in the reservoir, blow by gasses and air that have been entrained in the oil, aspirate out of the oil and collect in the reservoir. Vapor conduits can connect the lubricant reservoir with an induction system of the engine so as to draw out and dispose of the air and/or blow-by gasses.
One aspect of the invention includes the realization that certain vehicles, such as personal watercraft, are sufficiently maneuverable that oil within a lubricant reservoir can be displaced sufficiently violently to cause liquid oil to reach a vapor outlet in the top of the reservoir. When oil reaches the vapor outlet, it can temporarily clog a vapor conduit. Additionally, if such a vapor conduit is connected to the induction system of the engine, the liquid oil can be drawn into the induction system and thereby soil or damage induction system components.
Another aspect of the invention is directed to a watercraft having a hull and an engine supported by the hull. A lubricant reservoir defines an interior portion configured to pool lubricant for the engine and includes a vapor outlet. The watercraft, also includes a breather baffle arrangement disposed between the interior portion and the vapor outlet. The baffle arrangement includes a plurality of plates, each having an aperture, the apertures on adjacent plates being offset from eachother.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.